Abstract: This article takes as its focus the modern-day notion of populism as political discourse style and applies it to English Civil War propaganda language in order to see whether certain discourse strategies identifiable as populist may be consistent over time. In this regard, I follow Moffitt’s (2016) identification of three indexes of populism, i.e. “appeal to the people vs the élite”, “bad manners” and “crisis, breakdown or threat” and I attempt to detect and measure their level of occurrence in English Civil War news discourse through a corpus-assisted discourse methodology. My object of inquiry is the Parliamentarian periodical Mercurius Britanicus, which came out in August 1643 in order to counterattack the propaganda of the Royalist Mercurius Aulicus in the context of an ideological and military confrontation between the king and the Parliament. Both newsbooks are contained in the Florence Early English Newspaper Corpus (FEEN) which is available on the CQPweb Corpus Query System. The 16 issues of Britanicus, covering the period from 5 September 1643 to 7 October 1644 are compared to the 22 issues of Aulicus stretching over the same years. The results of the keyword and concordance analysis reveal that the three indexes of populism characterize the political style of Britanicus’s editor and that some of the features of modern-day media logic were already at work in Early Modern English propaganda discourse. This suggests that populism as discourse can be detached from contemporary politics to find interesting applications in the field of historical media discourses as well.